<!DOCTYPE html>

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>欢迎页面</title>
    <style>
        .welcome {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            margin: 15px;
            padding: 15px;
            color: #393D49;
            text-align: center;
            font-size: 20px;
            background-color: #fff;
        }
    </style>
</head>

<body>
    <div class="welcome">欢迎使用后台管理系统</div>
</body>

</html>